In automatic transmission systems of motor vehicles and similar machines, transmission fluid is stored, delivered, transferred or processed through rigid enclosed passages, chambers, orifices, mechanisms, or pumping/metering devices, all of which require regular internal cleaning to ensure proper service and system life. Such cleaning also enhances cost effective operation because fluid contaminants, deposits of additives or by-products of the automatic power transmission process, can foul and cause premature wear to system components, or otherwise inhibit the performance and delivery characteristics of the system.
If contaminants, such as dirt, oil sludge, gum, varnish, burned oil, deposits of worn out parts, residues of transmission additives, etc., are not properly flushed out of the automatic transmission system, they are likely to cause:
Slow and hesitant acceleration PA0 Rough, skipping, slow, erratic shifting, incorrect shifting points, excessive creep and abnormal vibration while shifting gears automatically PA0 Gear position slippage or lock-up PA0 Premature transmission fluid burn-out causing excessive fluid consumption and overheating PA0 Premature transmission component wear causing rapid deterioration of system performance, as well as other symptoms. PA0 U.S. Pat. No. 4,197,140 to Swan PA0 U.S. Pat. No. 4,520,773 to Koslow PA0 U.S. Pat. No. 4,606,311 to Reyes et al. PA0 U.S. Pat. No. 4,671,230 to Turnipseed PA0 U.S. Pat. No. 4,787,348 to Taylor PA0 U.S. Pat. No. 4,877,043 to Carmichael PA0 U.S. Pat. No. 4,989,561 to Hein et al. PA0 U.S. Pat. No. 5,097,806 to Vataru et al. PA0 U.S. Pat. No. 4,127,160 to Joffe PA0 U.S. Pat. No. 4,520,773 to Koslow PA0 U.S. Pat. No. 4,606,311 to Reyes et al. PA0 U.S. Pat. No. 4,787,348 to Taylor PA0 U.S. Pat. No. 4,877,043 to Carmichael PA0 U.S. Pat. No. 4,989,561 to Hein et al. PA0 U.S. Pat. No. 5,097,806 to Vataru et al.
If the above problems are not resolved in a timely manner, an expensive transmission overhaul is likely to be required.
The industry is well aware of the problems and difficulties encountered in servicing automatic transmission systems. The most common method for avoiding these problems is to change transmission fluid periodically. However, due to the design of most current automatic transmission systems, a typical fluid change replaces only from about 25% to slightly more than 55% of the used fluid.
The traditional method of changing automatic transmission fluid is to remove the dirty fluid in the pan by manually opening the pan or by withdrawing the fluid using a suction tube inserted through the dipstick tube, followed by filling the pan with fresh transmission fluid. When the pan is removed, it is also necessary to replace the gaskets, replace the filter and reinstall the pan. These servicing methods leave about 45% to 75% of the contaminated or burned fluid inside the cavities and components of the transmission system. For example, the torque converter, valve body, clutch chambers, passages, etc., all retain a large amount of used automatic transmission fluid, even after such a fluid change.
To replace all of the used transmission fluid, the only other option has heretofore been a complete automatic transmission system overhaul. However, this drastic and costly method is obviously not preferred for normal transmission service.
Other proposed solutions to automatic transmission system servicing problems are in common practice today. These include the use of aftermarket transmission fluid additives between fluid changes. Such additives generally improve the physical or chemical properties of the transmission fluid. For example, they can increase viscosity, improve heat transfer characteristics, and inhibit oxidation of internal components.
Also practiced is the addition of an aftermarket transmission system detergent solvent just before each fluid change. The mixture of detergent solvent and used transmission fluid circulates within the system to dissolve and dislodge contaminants while the transmission system operates under normal conditions, i.e. with the engine turned on. After this "cleaning operation" is completed, the traditional draining method is applied to remove the mixture of used transmission fluid and detergent solvent. However, as mentioned before, only 25% to 55% of the fluid mixture is actually removed in this way.
From the above discussion, we have concluded that traditional methods of changing fluid in automatic transmission systems leave considerable amounts of used transmission fluid behind. Since it is almost impossible to replace all of the used transmission fluid without disassembling the transmission system, regular flushing of automatic transmissions is seldom carried out. Therefore, vehicle and equipment owners have not been able to obtain a completely clean automatic transmission system. In fact, traditional methods of servicing automatic transmission systems only prolongs the inevitable--failure of the automatic transmission system due to contamination of the transmission fluid. In the absence of an improved alternative service method, deterioration and early failure of automatic transmissions is expected and tolerated. If a vehicle owner tries to rectify the situation by adding aftermarket additives or using detergent solvent, damage is likely to be even more severe in the long run. In addition to the large amount of used fluid left in the transmission, detergent solvents or expired additives remain inside the automatic transmission system. These solvents or additives are generally not beneficial if allowed to remain in the automatic transmission system. They can lead to unpredictable results and side effects on various system components. Moreover, if different additives or detergent solvents are used, unwanted chemical reactions can occur between them.
In view of the foregoing, there has long been a need for a simple, effective, and inexpensive method and system capable of removing all of the used automatic transmission fluid and embedded contaminants from the internal passages and chambers of an automatic transmission system without complete disassembly of the system.
The fuel systems of internal combustion engines, where fuel is stored, delivered, transferred or processed through rigid enclosed passages, chambers, orifices, mechanisms, or pumping/metering devices, also require regular internal cleaning to ensure proper service and system life and to assure cost effective operation. If cleaning is not performed, fuel contaminants, deposits of additives, or by-products of the combustion process can foul and cause premature wear to system components, or otherwise inhibit the performance and delivery characteristics of the system.
Moreover, the significance of flushing the fuel system of the internal combustion engine without disassembly of the fuel system is well known, as discussed in the following U.S. patents:
Therefore, in addition to the current need for an automatic transmission cleaning and draining apparatus, it is also desirable to provide the additional benefits of flushing the fuel system of an internal combustion engine without troublesome field modification.
The following patents relate to systems for the cleaning and/or diagnosis of automotive fluid systems:
Joffe teaches a method and an apparatus for flushing debris from a liquid circulation system, such as the cooling system of a water-cooled vehicle. This teaching is primarily applied to a vehicle cooling system and would not work on either an automatic transmission system or a fuel system of an internal combustion engine. Even in the context of flushing cooling systems, however, the method and apparatus of the Joffe patent do not permit complete fluid exchange because of the thermostat built into the cooling system between a radiator and its associated engine block. Because the apparatus is designed for use when an engine is not operating, it is assumed that the thermostat will be in a closed position, blocking all coolant flow in that important branch of the cooling system. In order to overcome the disadvantages associated with a partially blocked cooling system, the Joffe patent requires three separate connections to the cooling system and a complicated series of flushing steps. Even then, complete exchange of coolant is not achieved.
Koslow teaches a method and an apparatus for cleaning and testing the fuel injection system of a vehicle without disassembling the fuel injectors. The apparatus includes a device for feeding a solvent-fuel mixture, a control system and a series of connectors. The method includes a testing procedure which does not require disassembling the injectors. A critical step is running the apparatus to measure the flow through the fuel injection valve via a flow meter.
Reyes et al. teaches a method and an apparatus for cleaning the fuel injection system of a vehicle without disassembly and includes a device for feeding a solvent-fuel mixture into the supply system of the engine, and a control system for cleaning the injectors while running the engine.
Taylor describes a method and an apparatus for cleaning the internal body of a diesel engine, such as its internal components, injection pump, fuel injectors, fuel lines and so on. This teaching is primarily for carbon deposits and includes a fuel supply system, a chemical tank, filter means and other components.
Carmichael describes an apparatus on a cart with wheels to transport the apparatus to an engine to be serviced. The apparatus contains means for delivering a cleaning solution under pressure to the engine. However, it is suitable only for cleansing the fuel system of an internal combustion engine.
Hein et al. describes a method and an apparatus for cleaning the intake system of an internal combustion engine. Means are provided for injecting solvent directly into the engine intake system and varying the duty cycle or timing of the injections, thereby controlling the solvent flow. A pumping unit and a solvent holding tank are included. In operation, normal fuel flow to the engine is disconnected and the engine runs solely on the combustion of the solvent introduced by the injector through the air metering block of the apparatus. Because of this mode of operation, the apparatus is suitable for cleaning only the air intake system, intake valves and combustion chamber. Other parts of the engine, such as the fuel delivery system, cannot be cleaned.
Vataru et al. describes a method of cleaning internal combustion engine fuel injector structures, valves and combustion chambers by employing a canister containing a prescribed mixture of engine fuel and cleaning solvent. The mixture is discharged into the engine components using high pressure gas to charge the canister. However, the described method is limited to automotive fuel injection system use and does not include any diagnostics of the system being cleaned.